ASGM is usually carried out using the simplest technical means, is often informal, i.e. without a clear legal status, and is sometimes even clearly illegal. Digging gold means digging money and therefore attracts many people, mostly from precarious social backgrounds. It is estimated that 700 tonnes of gold are produced annually worldwide from artisanal mining, which is around 20 percent of annual global gold mining production. Depending on the legal status of its origin, gold from ASGM is also a source of smuggling and corruption and therefore poses a complex problem not only for the countries of origin, but also internationally.

One of the ASGM's hot spots is the Amazon rainforest, particularly the region along the Brazilian tributary Tapajós. Countless mines, so called garimpos, are hidden in the dense rainforest and are very difficult to access, usually only by aeroplane or boat. Due to negative public opinion and partly also because of the criminalisation of ASGM, extensive scientific analyses are rarely possible in these mines. However, our research team, with the special help of Professor Bernhard Peregovich from the Brazilian Federal University in Santarem (UFOPA), was able to visit and analyse around 50 different sites. Not only the ecological conditions were analysed, but also the living conditions and how this can be incorporated into a social assessment of the product gold[ii] . It became clear that the environmental problems in the Amazon rainforest cannot be solved without significantly improving the social situation for the people. However, this requires a stronger role for the state in one of the most remote regions of the world.

Since the 1990s, strong efforts have been underway worldwide to reduce the use of mercury, including in the watershed of the large Amazon tributary Tapajós. This is being achieved through the use of distillation apparatus, known as retortas, and the recovery of mercury. However, its use depends on various factors: the cost, the education of the gold miners (garimpeiros) and their knowledge of the harmful effects of mercury. At the beginning of our study, it was unclear whether the retorts were actually being used and how much mercury was being retained. For a long time, it seemed practically impossible to carry out on-site inspections, as the mines are hardly accessible to outsiders. The remote locations are difficult to reach, usually only by boat or aeroplane. Above all, however, the distrust of the garimpeiros must be overcome.

Our study now shows that the utilisation rate in the Tapajós region is very high and that the retention rate of mercury is also high. Nevertheless, considerable quantities of mercury are still being released into the environment. The question arises as to how mercury can be completely eliminated from the gold extraction process and what technical means and expertise are required for this. Above all, however, gold mining - even in ecologically sensitive regions such as the Amazon rainforest - must be brought out of illegality, mining permits must be made easier to a certain extent, but at the same time they must be linked to high environmental and occupational safety requirements and strictly monitored by the state. In addition to reducing mercury emissions, the recultivation of the old gold mines plays an important role in ensuring that secondary forest can form more quickly. More attention must be paid to the impact on river systems and their flora and fauna, as these are massively affected by the stirring up of sediment. This would require further extensive research projects, which must not only lead to research reports, but also to concrete measures on the ground as quickly as possible.

Artisanal gold mining is an important topic in development projects of industrialised countries and in the work of numerous NGOs. Many initiatives support alternative mining projects or cooperatives and endeavour to comply with ecological and social standards. In many such projects, great attention is paid to the elimination or reduction of mercury. However, the high amount of energy required to extract gold remains largely unnoticed. As the energy in the ASGM comes exclusively from fossil sources, mostly from diesel fuel, this is associated with high greenhouse gas emissions. For this reason, the energy consumption was recorded very precisely in the project. It is generally known that the extraction of gold has an extremely high carbon footprint. We have proven that this also applies to the ASGM. Artisanal mining generates around 16,000 kilogrammes of CO2 emissions per kilogramme of gold. By comparison, the figure for copper is only around 3 kilogrammes. This is why the mining of gold is and remains an ecologically questionable undertaking, while at the same time 200,000 tonnes of gold are still in circulation, i.e. half  of it is stored "dead" in the world's  banks.

There is talk of the decarbonisation of industry worldwide, including in the mining industry. This is a sore point for ASM. This is because alternative systems based on renewable energy would be required to replace diesel fuel for the equipment. This would require a high level of investment, which the people affected are rarely in a position to make. There are also technical questions as to whether the high-tech systems can be used sensibly in the jungle and, above all, whether it would induce urbanisation processes in the remote rainforests and thus indirectly endanger their existence.

The example of gold mining therefore also demonstrates the complexity of  sustainability. The ecological goals can only be achieved here by improving the social and economic conditions of the people and the governance of gold mining. It seems unrealistic to us to ban gold mining. It will always be a lure for people around the world. But the goal must be formalisation, i.e. clear rules for ASGM and, above all, state supervision. Care must be taken to ensure that ecological and social standards are adhered to.

On the consumer side, honest facts are needed. People are quick to advertise green gold or fair gold. But gold from mining, including from the ASM, has a high ecological footprint. The best option would be to increase the recycling of gold, as the carbon footprint would then be several orders of magnitude lower[iii] . However, this requires tracking the global gold supply chain, preventing smuggling and the criminal re-declaration of primary gold as recycled gold.

[i] Intergovernmental Forum on Mining, Minerals, Metals and Sustainable Development (IGF). (2017). Global Trends in Artisanal and Small-Scale Mining (ASM): A review of key numbers and issues. Winnipeg: IISD

[ii] Springer, S.K., Peregovich, B.G. & Schmidt, M. Capability of social life cycle assessment for analysing the artisanal small-scale gold mining sector-case study in the Amazonian rainforest in Brazil. Int J Life Cycle Assess 25, 2274-2289 (2020). https://doi.org/10.1007/s11367-020-01828-3

[iii] Fritz, B., Aichele, C. & Schmidt, M. Environmental impact of high-value gold scrap recycling. Int J Life Cycle Assess 25, 1930-1941 (2020). https://doi.org/10.1007/s11367-020-01809-6